After the choice fell on external filters, it is necessary to more accurately and more carefully choose the model of the right device. The first thing to pay attention to is the level of performance of such a filter. This value is measured in units of volume per hour, that is, the amount of water that can clean the filter in one unit of time. The main recommendation is that this parameter is approximately equal to three volumes per hour. For example, there is an aquarium in which the volume is 100 liters, it requires a filter whose performance is 300 liters per hour.
In addition to the volume, it is worth paying attention to the type of fish that will live in the aquarium, if these are large specimens, by the type of cichlid, or goldfish, in this case you need a more powerful filter. This is due to the fact that large fish eat respectively, and the more they eat, the more various waste can remain. If the aquarium is inhabited by small species, then in this case the ratio of three volumes of the aquarium per hour will be sufficient. It is worth remembering that sometimes manufacturers can overestimate the performance indicator – this is a kind of marketing move. It is always better to take a filter with a margin, if there is a lot of power, it is better to put an additional glass tube at the output, which will reduce the flow. Worse when the power is not enough.
In addition to performance, a very important criterion is a filler that is used in the filter. The type of filling can be curtained from the necessary tasks. The filters can use filter elements from a sponge, tangled fishing line, from ceramics, various synthetic winterizes, and even activated charcoal. To date, there are a lot of such fillers, and the choice depends only on the type of work performed, as well as on the tasks.